Wood siding has been used for many years in the construction of homes and other buildings. However, wood siding has several disadvantages, including regular painting for protection, and eventual rot or other breakdown of the wood material.
In order to retain the visual effect of siding, yet overcome the problems associated with wood, alternative materials such as metal and plastics have been utilized to simulate wood siding. Metal siding is typically formed of aluminum or steel, while plastic siding is conventionally formed from polyvinyl chloride, more commonly referred to as vinyl. In both types of siding, the bottom margin of each panel is bent inwardly and then upwardly to form a longitudinal channel flange with an upstanding inner leg, and the top portion of each panel is formed to provide an outwardly and downwardly projecting longitudinal lip corresponding to the channel flange of an adjacent panel. The panels are conventionally secured to a wall along their top portions, above the projecting longitudinal lip, utilizing fasteners driven through a nailing flange along the top of each panel.
One problem that is common with both metal and vinyl siding is in the expansion and contraction of the siding with changes in temperature. Because of this expansion and contraction, it has been common to attach the siding utilizing longitudinal nail slots provided in the nailing flange of each panel. The nails were then driven into the nail slots a sufficient distance to support the siding, but not far enough to grip the siding to prevent slidable movement along the nail slots.
In order to avoid splicing or overlapping horizontal lengths of siding, it is becoming increasingly common to provide longer lengths of siding which extend horizontally across an entire wall surface. These longer lengths of siding have posed problems in attachment because of the additional expansion and contraction which occurs. Conventional siding nailing flanges have nail slots approximately 1/8 inch in width and approximately 1 and 1/8 inch in length. Thus, the maximum amount of expansion or contraction is approximately 9/16 of an inch in either direction. With the use of long lengths of siding, this distance is not sufficient, and the siding can "ripple" or bulge where fastened during extreme expansion or contraction.
Attempts to deal with this problem have resulted in failure. Increasing the length of the nail slots in the nailing flange results in a narrow support strip above the nail slot, which is insufficient to support the siding, and causes rippling and bulging. Attempts to strengthen the nailing flange to permit longer nail slot lengths have also failed. An increase in the thickness of the nailing flange causes the nailing flange to expand at a different rate than the remaining portions of the siding panel, again causing rippling and/or bulging.
Another problem with vinyl siding is the low structural strength of the nailing flange when a nail is inserted through the nail slot. Because of the small cross-section of the nail, and the narrow width of the material between the nail slot and upper edge of the panel, the vinyl material will not support a great amount of weight, and is easily ripped upon the application of a downward dynamic force on the panel. Thus, application of vinyl siding to manufactured homes, which are transported over the road, has a significant problem with loss of vinyl siding during transit.